1. Field of the Invention
The invention relates to the field of printing systems, and in particular, to methods and systems for color conversions with toner/ink limitations.
2. Statement of the Problem
In color printing, displaying, and reproduction, the term gamut represents the set of colors that a color-reproduction device is physically able to generate. Every device that displays or reproduces an image, such as a printer, monitor, scanner, or digital camera, may have its own unique color gamut. When an image is transferred from one device to another, the color gamut of each device is examined to closely match the color in the transferred image. That is, an attempt is made to closely match the color gamut of the image originating device in the device to which the image is being transferred so as to provide the most aesthetically pleasing color conversion. For example, the color gamut of a digital camera is generally greater than the color gamut of a printer. When color values of the digital camera color gamut are mapped to the color gamut of the printer, the conversion process generally requires intense analysis to ensure that the print quality is of sufficiently high quality.
A competing interest in color printing, however, regards the costs associated with toner and ink. While a certain amount of toner or ink is necessary for maintaining relatively high quality printing, toner/ink typically account for a substantial portion of the printing expenses. Traditionally, toner/ink has been conserved via an under color removal (UCR) process. In C, M, Y, K (Cyan, Magenta, Yellow, and Black) color printing, UCR is the process of eliminating certain amounts of cyan, magenta, and yellow that add to the dark neutral color, such as black. These colors are replaced with the less expensive black toner during the color separation process. However, black toner alone is not sufficiently dark and thus tends to produce relatively dull looking images.
In inkjet applications specifically, ink coverage is also limited to avoid “bleed through” where the ink actually saturates the paper. For example, in C, M, Y, K printing, the ink is scaled and/or clipped for each color component so as to not saturate the printing medium (e.g., paper). This process, however, affects color quality in the highly saturated and dark neutral regions that require more C, M, Y, K components. Thus, there is a need for improved means for limiting toner so as to reduce the costs of printing and/or bleedthrough without sacrificing print quality.